Conventional magnetic heads typically employ lapping to fabricate structures within the head. For example, lapping is typically used in processing a read sensor in a read transducer. Lapping determines the stripe height, or length measured from the air-bearing surface (ABS), of the read sensor. Similarly, lapping may be used in fabricating the main pole of a conventional write transducer. The nose length, or the distance from the ABS at which the pole tip widens, may also be determined through lapping.
In order to control lapping an electronic lapping guide (ELG) is typically used. FIG. 1 depicts a top view of a conventional ELG 10. The conventional ELG 10 is essentially a resistive stripe. Thus, the conventional ELG 10 is coupled with leads 14 and 16 that are used to determine the resistance of the conventional ELG 10. The conventional ELG has a length l from the surface 12 being lapped. As lapping continues, the surface 12 is worn away, and the length of the conventional ELG 10 decreases.
FIG. 2 is a flow chart depicting a conventional method 30 for performing lapping using the conventional ELG. The conventional method 30 is described in the context of the conventional ELG 10. The resistance of the conventional ELG 10 is measured during lapping of the transducer, via step 32. The current length of the conventional ELG 10 is determined based upon the resistance measured in step 32 and the sheet resistance of the conventional ELG 10, via step 34. The sheet resistance may be determined in a conventional manner using a conventional Van der Pauw pattern (not shown) which is provided on the substrate on which the magnetic transducer is to be fabricated. The conventional Van der Pauw test pattern is a well known pattern that may be used to determine sheet resistance of a stripe, such as the conventional ELG 10. Thus, after step 34, the length corresponding to a particular measured resistance for the conventional ELG 10 is known.
The lapping is terminated when the resistance of the conventional ELG 10 indicates that the desired length of the conventional ELG 10 has been reached, via step 36. Because the conventional ELG 10 and structure, such as a read sensor or pole, both exist on the transducer being lapped, the lengths of the conventional ELG 10 and the structure change with lapping. Consequently, the lengths of the read sensor or pole may also be set in step 36.
Although the conventional method 30 and conventional ELG 10 function, there may be variations in lapping. In particular, the method 10 may not provide the desired length in the structure being fabricated. For example, the pole and read sensor may not have the desired nose lengths and stripe heights. Consequently, once the transducer is completed, it is tested. It may then be determined that some portion of the transducers do not function as desired. As a result, additional inventory is maintained or additional transducers are fabricated to ensure the number and quality of transducers desired are available.
Accordingly, what is needed is an improved method for providing and using an ELG in a magnetic transducer.